OK, I have a K-01 and tried it with an M style lens (Takumar 135mm) and the K-01 is a bit quirky with the M style lenses. The K-01 does have a mechanical shutter which stays closed when the camera is off and opens up as soon as the camera is turned on. When you take the shot, the shutter closes, then fires for the shot, then opens again. Realistically, it is always in a Live View mode.
It seems when you stop down the lens to ascertain an f/stop-to-shutter speed exposure setting (more on this in a moment), the viewfinder/monitor automatically compensates for the lack of light, bumping up the image brightness on the display. This makes it very hard to judge the exposure before shooting, so you pretty much have to guess and chimp the shot. The aperture is working as the DoF increases as you stop down, but the effect of exposure on the monitor is neutralized. I was hoping the K-01 would provide changes to the exposure meter, but there is no indication for this in the camera monitor display.
To stop down the lens before the shot, place the camera into M mode. Make certain the Aperture Ring option is set to Enabled, and when you press the +/- button next to the Red button on the top of the camera, the lens will stop down. This will work as a DoF preview nicely, but not work well for exposure settings, as mentioned. Another option, put the camera into Tv mode and let the shutter speed float as needed. This works quite nicely and if you need to over or underexpose an image to get the shot you want, then use that same +/- button to adjust the exposure compensation.
Remember, these older style M lenses were never designed with a mirrorless camera in mind!
---------- Post added 08-30-16 at 11:11 PM ----------
Originally posted by vonBaloney Of course, I was just making a distinction between being powered up or not -- if memory serves the K-01 doesn't open the lens up until the power is on unlike all the SLRs.
Yes, your memory serves you well. The aperture stops down when off, opens up as soon as the K-01 is powered on.